Abstract: BACKGROUND ＆ AIM: To establish an automatic scoring system based on a single_laser flow cytometer for detection of frequencies of micronucleated reticulocytes from human peripheral blood. MATERIAL AND METHODS: Based on the automated scoring system for detection of frequencies of micronucleated polychromatic erythrocytes from rat marrow set up by our laboratory,magnetic cell separation technique was introduced into automatic micronucleus test this time to enrich reticulocytes from human peripheral blood and acridine orange staining was used to calculate the frequencies of micronucleated reticulocytes from human peripheral blood by a single_laser flow cytometer. RESULT: 20％ to 90 ％,but no significant difference was seen for the same healthy donor within a relative long time during which several separation tests were performed；five distinct cell populations could be clearly seen which were reticulocytes,micronucleated reticulocytes, residual normochromatic erythrocytes ,micronucleated normochromatic erythrocytes and nucleated cells respectively；the baseline of frequency of micronucleated reticulocytes of healthy donors was 2.36 ‰,while corresponding to different cumulative dose of 0,4,10,20,30,40 or 50 Gy,the mean frequency of micronucleated reticulocytes of nasopharyngeal cancer patients was 2.97 ‰,29.37 ‰,57.90 ‰,69.05 ‰,62.58 ‰,51.19 ‰ or 50.07 ‰ respectively. CONCLUSION:An automatic scoring system based on a single_laser flow cytometer for detection of the frequencies of micronucleated reticulocytes from human peripheral blood has been established.

Key words: micronucleus test, flow cytometry measurement, automatic measurement, human peripheral blood